The invention is directed to a long field lighting fixture or light fixture with a linear lighting field, which is capable of forming a light screen and has a trough-shaped lamp housing securable to the ceiling of a room via suspensions or directly at whose end walls connector elements are provided for optionally joining individual long field lamps directly to one another to form a light screen or a ribbon of light fixtures.
Lighting equipments for large-area rooms are often realized in the form of light screen systems wherein a plurality of lighting fixtures, are frequently placed directly against one another, to form a straight-line lighting fixture system that appears closed. In large-area rooms such as assembly, manufacturing or storage halls but also in sports arenas, such light screens are preferably arranged in a longitudinal direction of such a room, and also in a plurality of rows parallel to one another.
EP-B1-0 486 714, for example, discloses light screen systems of said species. The bearing structural element in such a light screen system is a carrying rail having a length that can accept a plurality of lighting fixture inserts. A through wiring is usually provided in the carrying rail for the electrical supply of the light sources. The lighting fixture inserts often have a base member with an essentially flat carrying plate that is attached to the carrying rail during assembly of the light screen and is secured thereto with turn-lock fasteners. The carrying plate serves as a receptacle for all electrical as well as mechanical elements of a lighting fixture. All of these elements except lamp sockets are thereby preferably pre-mounted on the upper side of the carrying plate and arranged such that they immerse into the cross-section of the carrying rail when the lighting fixture insert is mounted. In many known light screen systems, a lamp reflector, a lamp housing together with grid or a lamp covering are individually detachably secured to this carrying plate of a lamp insert. The same turn-lock fasteners with which the carrying plate itself is to be fixed to the carrying rail are often employed for the fastening.
As a result of its modularity, this known structure of the light screen systems enables an extraordinary flexibility in the lighting fixture arrangement and selection, so that individual lighting jobs can be solved in different ways with such light screen systems. Added thereto is that, due to their modular structure, such light screen systems can also be adapted without further ado to changing demands made of the room lighting, for example given a different room use. One disadvantage of this basic format of known light screen systems having a plurality of individual components is the relatively high outlay caused by the inherently desired modularity, this being expressed in the tool, manufacturing and warehousing costs.
As derives from DE-C1-43 42 657, this disadvantage has already been recognized. This document discloses a lighting fixture unit for light screen systems whose special characteristic is that an illumination means therein, particularly in the form of one or more fluorescent lamps arranged in a lighting fixture unit, is no longer fixed to the carrying plate of the lamp insert but--via lamp sockets--is directly fixed to the carrying rail of the light screen system. This known lighting fixture unit for a light screen system thus foregoes a carrying plate inserted into the opening of the carrying rail, i.e. the plate is eliminated. Instead, the reflector unit of the lamp insert serves directly as a covering of the carrying rail that is open in the direction toward the illuminated surface. In order to be able to realize this simplification of the structural format of a lighting fixture unit for a light screen system, all electrical and mechanical components of a lighting fixture, including the sockets for the illumination means, are directly introduced into the free cross-section of the carrying rail and fixed thereat. The reflector arrangement with which the carrying rail is covered at its surface directed into the room must then be fashioned such that the sockets secured to the carrying rail can be plugged through the reflector arrangement or, respectively, that corresponding cutouts for the acceptance of the plug-in sockets are provided at their end edges.
Given this known solution, a certain disadvantage must be accepted in view of the assembly and maintenance friendliness in order to achieve a simpler and, thus, more cost-beneficial lighting fixture structure. Viewed from this point of view of cost benefit, however, the known solution can still not fully satisfy because the elimination of only a carrying plate means a relatively slight cost reduction compared to the disadvantages of less of a scope of variation thus accepted.
Further, lighting fixtures capable of forming a light screen are known and have a trough-shaped lamp housing which is either directly attachable to a ceiling or held by suspensions and the fixture has housing wall parts at the face side that can be directly attached to one another for forming a light screen or a row of light fixtures. A carrying rail is not utilized given these lighting fixtures; instead, the housings of the individual lighting fixtures are fashioned correspondingly stable and such that, in addition to accepting the illumination means and the reflector arrangement surrounding them, they also accept the electrical and mechanical component parts and also enable a through wiring when employed in a screen arrangement.
U.S. Pat. No. 3,599,911 discloses an example of such a lighting fixture capable of forming a light screen. Therein, end wall parts of the lamp housing are fashioned as punched sheet metal parts with angled-off edges via which they are secured to the lamp housing with screws or rivets. In order to be able to mutually anchor the end wall parts, the end wall parts have hooks and eyelets arranged in alternation. For joining end wall parts, these must first be placed against one another offset relative to one another in a transverse direction so that the hooks can be introduced into the corresponding eyelets. A transverse motion of the joined end wall parts is then required for locking the hooks. The assembly process for a light screen is therefore relatively involved and requires an additional adjustment in order to achieve an exact alignment of the joined lighting fixtures.
EP-B-0 264 857 also discloses a long field lighting fixture capable of forming a light screen wherein terminating plates are provided as adapter elements at the end walls of the lamp housing whose outsides comprise plug in frames respectively joining into one another in the fashion of stackable elements. Long field lighting fixtures can thus be attached to one another aligned by simply plugging the outsides of these terminating plates together. However, a further end cap is then required for the end-face termination of a single lighting fixture or the end of a light screen.